How to know if your rabbit is sick?

Eyes- clear of discharge or ooze (milkyness or haze is blindness)
Nose- Clear of discharge or wetness
Ears- Clean of gunk, bugs, rashes, or scabs/wounds/redness
Belly- Free of any UNUSUAL bumps and wounds
Neck- Free of bumps
Teeth- are even with one another, not overlapping (IMPORTANT= SEE MALECLUSION)
If all above is clear you should be fine, some other signs may be-